play with boost.python 2

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background

in 1, we have a basic work flow of boost.python. in reality, the C++ project may have multi headers, where define many structs/classes, and include nested structs. here we give an simple example of nested struct/class.

api_header.hpp

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typedef struct {
	float time; 
	float dx ;
	float dy ;
} AEB;
typedef struct {
	AEB out1 ;
} OP;

aeb.hpp

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#include <iostream>
#include <string>
#include "api_header.hpp"
class aeb {
    public:
        aeb() {}
	OP op_out ;
        void test_op(){
            (void) memset((void *)&op_out, 0, sizeof(OP)); 
            op_out.out1.time = 1.0 ; 
            op_out.out1.dx = 2.0 ;
            op_out.out1.dy = 3.0 ; 
            AEB o1 = op_out.out1 ;
            std::cout << o1.time << std::endl ;
        }
};

for each of them, we can write a separate wrapp files.

api_wrapper.cpp

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#include <Python.h>
#include <boost/python.hpp>
#include "api_struct.h"
using namespace boost::python;
BOOST_PYTHON_MODULE(api_wrapper) {  
    
    class_<AEB>("AEB", "aeb struct")
            .def_readwrite("time", &AEB::time)
            .def_readwrite("dx", &AEB::dx)
            .def_readwrite("dy", &AEB::dy) ;
    class_<OP>("OP", "OP struct")
            .def_readwrite("out1", &OP::out1);
}

aeb_wrapper.cpp

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#include <Python.h>
#include <boost/python.hpp>
#include "student.h"
using namespace boost::python;
BOOST_PYTHON_MODULE(aeb) {                                                                                                                                                                              
    scope().attr("__version__") = "1.0.0";
    class_<aeb>("aeb", "a class of aeb ADAS")
        .def(init<>())
        .def(init<std::string, int>())
        .def_readwrite("op_out", &aeb::op_out)
        .def("test_op", &aeb::test_op, "test op")
}

compared to previous blog, we had def_readwrite() to include the nested struct in aeb python module, which is dynamic linked during python runtime, so which requires to import api_header module first, then import aeb module.

build && test

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g++ -I/home/anaconda3/envs/aeb/include/python3.6m -I/usr/local/include/boost -fPIC wrap_api.cpp -L/usr/local/lib/ -lboost_python36 -shared -o wrap_api.so
g++ -I/home/anaconda3/envs/aeb/include/python3.6m -I/usr/local/include/boost -fPIC wrap_student.cpp -L/usr/local/lib/ -lboost_python36 -shared -o student.so
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import wrap_api
import aeb
s = aeb.aeb()
s.test_op()
a = s.op_out.out1 
a.time
a.dx

summary

this basic workflow is enough to package Matlab/Simulink ADAS models C++ code to Python test framework.